You need adjustable lowers at least in the rear to dial the pinion and center the tire in the wheel well. I actually needed my lowers short so my tire wouldn't rub the back of the plastic flare, and so I could have enough thread engagement on my uppers.

If you use just the uppers to adjust pinion then you likely won't have enough thread engagement with that high of a pinion angle. You need to use the lowers as well.